


The Favor

by Skylar102



Series: The Devil I Know [3]
Category: Lucifer (TV), Shadowhunters (TV)
Genre: Alternate Universe - Canon Divergence, Amenadiel is done with everyone, Angst and Feels, Attempt at Humor, Deal with a Devil, Gen, Light Angst, Lucifer just wants his buddy Alec to talk to him, M/M, Protective Alec Lightwood, Tags Are Hard, but what's new, especially Lucifer, is that too much to ask
Language: English
Status: Completed
Published: 2020-05-21
Updated: 2020-05-21
Packaged: 2021-03-03 00:54:24
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,610
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24306256
Author URL: https://archiveofourown.org/users/Skylar102/pseuds/Skylar102
Summary: Lucifer has come to cash in on his deal with Alec
Relationships: Magnus Bane/Alec Lightwood
Series: The Devil I Know [3]
Series URL: https://archiveofourown.org/series/1737094
Comments: 51
Kudos: 368





	The Favor

**Author's Note:**

> Oh boy y'all we are getting closer to the end of this series 😬
> 
> I may have one or two more fics planned for this, depending on if I want to break the next part into two fics or not. It might just be one long last fic, but I haven't even started writing it yet so we shall see!!
> 
> Also please note that this is Season 1 Lucifer and Amenadiel because I'm only on episode 5 of season 2 skldjfsdjfkd
> 
> Thank you once again to the lovely [Em](https://archiveofourown.org/users/thatnerdemilyj/works) for Beta'ing <3

“Alexander,” Lucifer cheers, walking towards Alec. Alec takes a step back and reaches for his blade only to grasp at air. He curses Magnus for not keeping his thigh holster on the clothes he swapped him into.

“It’s been so long. Look at you, you’re so,” Lucifer eyes him up and down with a smirk, “tall.”

“What did you do to them,” Alec demands. Lucifer halts two feet away from the Shadowhunter.

“I’m hurt, Alexander. Wounded really.” Lucifer presses a hand to his chest. “And here I thought you would be happy to see me. After all, your archery did improve, didn’t it? I think that at least deserves a thank you.”

“I’ll thank you once you release my friends and family.” 

“Not the scared Nephilim you were all those years ago I see,” Lucifer observes. “Unfortunately I cannot do that seeing as I wasn’t the one to do it. My brother thought it would be easier this way.”

“Your brother?” Alec asks. Fluttering is heard and a deep voice speaks up from the french doors leading to the balcony.

“Would you hurry up, Lucifer? I cannot freeze time for this long,” the dark-skinned man says as he maneuvers around the frozen bodies. 

“Always looking to ruin my fun, Amenadiel,” Lucifer groans. Alec stands up straighter at the name.

“Amenadiel,” Alec breathes out, eyeing the angel. Amenadiel sends him a gentle smile. Alec remembers the stories he learned in school about the angel before him. The firstborn angel, the eldest of them all. 

“You’re-You-,” Alec stutters out. “I don’t know whether to bow or not.”

“Oh for god’s sake,” Lucifer groans. “This is my time to shine, brother. You can go back to your bird perch so that Alexander and I can talk in private.” Lucifer makes a shooing motion with his hands at Amenadiel. Amenadiel ignores his brother’s childish comment.

“Pardon my brother’s behavior and to answer your question,” Lucifer guffaws behind Alec at the statement, “no, you don’t have to bow to me. You and your people have done enough to protect the mundane world. I should be bowing to you.”

“Amenadiel, stop bonding with  _ my  _ Nephilim friend,” Lucifer whines. “He made a deal with me, remember?” 

“And here you are complaining instead of telling the man what you need him for,” Amenadiel addresses. “So tell Mr. Lightwood what  _ you  _ need him for.”

“Lightwood-Bane,” Alec corrects under his breath causing the pair to him. Too many times in the past year he’s had to correct Clave officials of his name that he’s forgotten that he’s in the presence of the Devil himself and the First Angel and probably shouldn’t correct them.

“Look at you, you sly dog! Already hitched before you turned twenty-five,” Lucifer crows as he looks around the room. “Now who is the lucky lady that captured your heart.”

Alec can’t stop the snort that escapes his mouth. He tries to school his face when Lucifer turns his attention back to him. Lucifer eyes him curiously before he sees the lightbulb go off in the Devil’s head.

“So not a lady then,” Lucifer realizes and restarts his search for Alec’s husband causing Alec to tense up again. While Alec doesn’t mind that they know he’s gay, he would prefer if Magnus stayed out of this. “Eenie meenie miney.”

“Lucifer, we don’t have time for this,” Amenadiel sighs. “In about 10 minutes, the spell is going to wear off and I am not about to bail you out if the other Nephilim catch sight of you.’

“Now both you and I know that’s a lie,” Lucifer states. “It’s in your nature as a big brother to protect your younger siblings.”

“Not if the younger sibling is getting on my nerves,” Amenadiel grits out. “The longer you hold off on telling Mr. Lightwood-Bane about the case, the more deaths that will occur.” Alec perks up at the mention of a case while Lucifer seems to be ignoring his brother’s words, still eyeing each man in the room. Amenadiel sighs and looks at Alec apologetically. “The longer you put the detective in danger.”

This causes Lucifer to stop his quest to find Alec’s husband. He turns his attention back to Amenadiel with a look of concern? That can’t be right, Alec thinks. The Devil wouldn’t be friends with a mundane. Let alone a police detective. Lucifer squints his eyes before rolling them.

“Fine brother. You win.” Lucifer says and he turns his attention back to Alec. “For your end of the deal, you are to help me find the demon that is currently wreaking havoc in L.A.”

“L.A.?” Alec questions. “Why not go to the L.A. Institute and let them handle it?”

“In case you haven’t noticed angel boy, I am the Devil.” Lucifer gestures at his body. “I can’t just stroll up to the doors of the Institute and say ‘hello I’m the Devil and I have a demon problem.’” Lucifers seems to ponder at those words. “They would take me out before I even spoke now that I think about it. With all that fancy technology you lot have developed, they would see me coming from a mile away-”

“Lucifer,” Amenadiel interrupts. “The case.”

“Right, yes. There is a demon in L.A. who is currently killing mundanes in what seems to be a ritualistic style sacrifice. The detective seems to think it’s a cult whack job but we found a specific type of dirt that can only be found in Duduael.” Alec tenses at the word and a cold sense of dread shivers down his spine. Words are leaving his mouth before he can think.

“These killings,” Alec blurts, “there’s no signs of attack on the bodies, is there? And the dirt, it was found on the victims’ bodies?”

Lucifer and Amenadiel share a look.

“Yes,” Amenadiel answers slowly. “The bodies are untouched. There are no visible marks of an attack, just the traces of the dirt found on the bodies. There are also demonic sigils painted on their stomachs that mean that the demon is trying to resurrect someone. But how did you know that?”

“Because I know who is killing those mundanes,” Alec mutters. “Azazel.”

At the name of the Greater Demon, Lucifer lets out a boisterous laugh while Amenadiel is staring at him in shock.

“Azazel?” Lucifer says incredulously. “The ruler of Duduael, in L.A.? Don’t be ridiculous, Alexander. I would know if my brother was here on earth. He wouldn’t pass up the opportunity to see me.”

“Not if he’s using the same glamor he used when he was terrorizing us here in New York,” Alec rebuts. “Not even the High Warlock at the time could trace him. We had to summon him to us which did not end in our favor.” 

The screams of Magnus pleading to him while stuck in Valentine’s body ring through his head. Without thinking he turns towards his frozen husband who still has a fond smile on his face, holding his birthday cake. It’s the perfect reminder that his husband is still himself and alive.

“Is that the lucky man?” Lucifer notes, stepping up next to him. Alec glares at the man who’s busy checking out his husband. “You have good taste. You ever thought about spicing up the relationship by adding a third to your bed one night?”

Alec sputters at the question while Amenadiel sighs. Something tells him that this is not the first time Lucifer has asked that.

“Will you help us track him down?” Amedadiel asks.

“Oh, he doesn’t have a choice, brother, so there’s no need to ask,” Lucifer interjects, patting Alec on the shoulder. “This is non-negotiable I’m afraid. Seeing as this is the favor I ask in return for your archery skills.”

Alec clenches his jaw and looks away from him. He stares at all of his friends and family who are frozen with happy and content looks on their faces. He can’t take that away from them with this. Not after the scars that everyone had to bear after Azazel came after them the first time. 

“Okay,” Alec says, turning back to him while pointing at his friends and family. “But they can’t know about this.” Lucifer opens his mouth to say something, but Alec cuts him off. “I mean it. Azazel has already messed with them enough and they don’t need to know he’s back on earth. Especially my husband.”

“Oh, now there’s a story I need to hear once you join us in L.A.” Lucifer looks delighted at that and it makes Alec’s blood boil. He keeps his mouth shut not wanting to let his anger out at the remark. “Well do enjoy the rest of your birthday, Alexander. We shall see you bright and early tomorrow!”

Lucifer pats him on the shoulder just a tad too strong before he pushes him in the direction of his husband. Alec doesn’t get a chance to say anything as time unfreezes and everyone is cheering at him to blow out his candles. Magnus catches his panicked look, but Alec quickly schools his expression with a smile and leans down to blow out his candles. The room drunkenly cheers but Magnus doesn’t take his eyes off of Alec. Someone quickly takes the cake out of Magnus’ hands to cut it, too impatient to wait for the two to stop staring at each other.

“What’s wrong?” Magnus whispers, raising a hand to cup Alec’s face. 

“It’s nothing,” Alec rushes out, wincing. He knows that was too much and judging by Magnus’ expression, he knows it too. 

“We’re going to talk about whatever is making you panic once everyone is gone for the night,” Magnus says, patting his face. “I don’t know what’s going on, but we will discuss it.”

“Okay,” Alec whispers back. Magnus stares into his eyes for a moment before stepping away from Alec. He goes to get a slice of cake for both of them before Jace eats all of it and leaves Alec to stand in the living room alone.

Alec hates this, not being able to tell his husband about the deal. Though that’s not true. He could tell Magnus. Lucifer never said anything about not telling anyone.  _ He’s  _ the one that refuses to get his family involved. They are past all the bad that’s happened in their lives. They had enough in those few months to last a lifetime. Alec can’t rip that away from them.

The night goes on normally. Alec tries not to think about his end of the deal as he sits in the armchair. Tries not to think about the fact that Azazel is back on earth just across the country. Too close for Alec’s liking. Alec looks over to where Magnus and Cat are telling funny embarrassing stories about the other to the rest of the party. Laughter echoes through the loft at their tales and Alec lets the sound wash over him as he closes his eyes. 

When he opens them, he finds Magnus staring directly at him. He sends a reassuring smile to his husband. Magnus sends him a wary glance before returning the smile and going back to his conversation.

Later when the last guest is let out the door with a farewell, Magnus turns to focus his attention on Alec. Alec is cleaning up the plates and glasses from the party to keep himself occupied and tries not to think about the coming talk. He hears a snap and the familiar sound of Magnus’ magic and the mess from the party is gone. Alec sighs and turns to his husband whose arms are crossed. 

“You going to finally tell me what’s really bothering you?” Magnus asks, staring him down.

_ Now or never _ , Alec thinks, moving to the couch to sit down. He leans forward covering his face with his hands. He has to be careful what he says. If anything doesn’t come out like it’s the truth, his husband will catch on immediately. He truly does hate this. 

He doesn’t realize he’s pulling at his hair until he feels hands grab at his wrists, halting the movements. Looking up, Magnus is sitting on the coffee table looking at him with unbridled worry. Magnus gives a kiss to his hands before lowering them into his lap, intertwining their fingers.

“Alec, whatever is causing you stress, you can tell me,” Magnus mutters. “You know I would never judge you.”

“I know that, Magnus. It’s just-” he hesitates, looking down at their hands.  _ Now or never.  _ “My father has requested my assistance in L.A., immediately. I leave for the Institute first thing tomorrow morning.”

He hears an intake of breath in front of him, but he focuses on playing with Magnus’ wedding ring. One of Magnus’ hands releases its hold and cups his face, tilting it up. 

“I thought you and your father were on good terms?” Magnus questions.

“We are,” Alec agrees. “But this is so sudden and last minute. I know you were looking forward to the weekend with us and Madzie and this looks like it might take the whole week.”

“Alexander, things happen. I didn’t marry the head of an Institute thinking that plans may never get canceled or change. I would never be upset by you having to go do your job. Even if I was, I wouldn’t hold it against you.”

“I know, Magnus, but I hate how many times I do it to you,” Alec says, every word coming out of his mouth tasting sour. “You deserve to be able to spend time with your husband.”

“How many times have I had to cancel a date night in the last year due to an emergency with a client?” Magnus laughs. “You never got upset with me about those times, why would I be upset when it happens to you?”

“You can’t deny that I do it more, though.”

“That may be true, but you more than make up for it later,” Magnus argues, a mischievous smile appearing on his face. “In multiple ways I might add.”

“Stop,” Alec huffs, pushing his knee against Magnus’. 

“I’m serious,” Magnus continues on. “I always look forward to how you make it up to me. Oh, that one night on the balcony is one I won’t forget.”

“Magnus!” Alec laughs. He feels heat rising on his cheeks. He pulls his giggling husband into his lap, kissing the smile off his face. Magnus winds his arms around his neck as he wraps his around Magnus’ waist. 

“I love you,” Alec whispers, leaning his forehead against Magnus’.

“I love you too, Alexander.” 

Alec smiles at him. How lucky he is to call this man his husband. It doesn’t help ease the guilt that’s eating away at his stomach, but knowing his husband will be nowhere near the Greater Demon that caused him to relive memories of his childhood makes it just a tad easier. 

“Come on,” Magnus says, pressing a kiss to Alec’s forehead before standing up. “We still have to celebrate your birthday.” Magnus walks towards the leftover cake on the table and takes a slice.

“I don’t think I could eat another slice,” Alec groans at the idea. Magnus turns back to him with a smirk and heated eyes.

“So you don’t want me to eat this off you?” Alec perks up at the question and watches Magnus disappear into their bedroom. “That’s a shame... Guess I’ll just have to eat this by myself.”

Alec pushes off the couch and chases after his husband, closing the bedroom door behind him. 

Maybe it wasn’t all that bad of a birthday.

**Author's Note:**

> If you want a threesome with Alec/Magnus/Lucifer say I 
> 
> I'll never write it but just imagine 🤤🤤
> 
> As my Beta Em put it "Side chapter where Magnus eats cake off of Alec and all Alec can think about is inviting Lucifer into their sex life??? 👀"
> 
> Come talk to me on [Twitter](https://twitter.com/Skylar10211)
> 
> Want to talk about Shadowhunters with other fans?
> 
> [Join our Discord!](https://discord.gg/fhbfNFA)


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